Light Up Your Life

With the short, dark days of winter upon us, many people experience some degree of the winter blues. But some suffer from a more severe form of seasonal depression now known as seasonal affective disorder (SAD). Researchers estimate that as many as 10 million Americans suffer from SAD, 75 percent of them female. Symptoms, which usually set in around September or October and last through March or April, include decreased energy, more hours of sleep, and social withdrawal. Many researchers believe the disorder stems from the decrease in sunlight during the winter months, which can cause hormonal imbalances, in particular increased levels of the pineal secretion melatonin.

Although no definitive test to diagnose SAD exists, most patients have high levels of melatonin in their blood, possibly because their body's melatonin production doesn't properly shut down in the morning. SAD also appears to have a genetic component, with entire families prone to winter melancholia, particularly those living far enough north to experience lengthy periods of darkness for many months of the year.

Making the diagnosis of SAD can be tricky because it can mimic several other depressive disorders. In general, if you notice that shorter, darker days consistently cause you to feel down, irritable, and lethargic, you may have this form of depression and should seek out a proper diagnosis from a professional. Your friends and family may notice your low spirits before you do—so pay attention to their observations.

If you do receive a diagnosis of SAD, don't despair. Light effectively treats the disorder. In fact, studies show that light therapy is 60 percent to 90 percent effective in treating SAD patients. If you live in the far north where sunshine in winter is limited, or if you have a more severe case of SAD, natural light may not do the trick—you may need to seek out an alternative source of light. Although artificial indoor light doesn't put an end to SAD, high-intensity fluorescent light therapy can work wonders.

How Light Therapy Works

Researchers have long explored how light affects mood. Melatonin, secreted deep inside the brain by the pineal gland, is the intermediary between mood and light. Light striking the retina of the eye regulates the pineal gland, as does the "master" of hormonal control, the hypothalamus gland. Alteration in pineal function has been implicated in numerous studies, not only in SAD, but also in jet lag, breast cancer, miscarriage, other reproductive problems, and sleep disorders.

Melatonin production increases as darkness falls, triggering sleepiness. Because darkness stimulates melatonin production, it is possible that people with SAD are overproducing melatonin. Interestingly, the pineal gland also secretes the "feel-good" neurotransmitter serotonin—more so when there's more light, at the same time reducing melatonin secretion.

Spend as much time as possible outside this winter—twenty minutes daily is a minimum requirement for well-being. The current treatment of SAD, when natural sunlight is not available during winter months, is exposing yourself to broad-spectrum light, which does not include harmful ultraviolet (UV) rays. This means sitting in front of a light box. The timing and intensity of the light are of utmost importance. Getting extra light in the morning is more effective than light therapy later in the day because early-morning light simulates a natural sunrise and activates your body's natural circadian rhythms. Upon waking, you place yourself within 10 feet of a 10,000-lux bulb or a series of bulbs totaling 10,000 lux (lux is a standard measurement of a light's intensity) and stretch, meditate, or read for 20 minutes. Most people see benefits within a few days, but treatments need to remain consistent. Rarely, anxiety or headaches result from bright-light therapy, in which case the recommendation is to start with half the time and twice the distance from the light and work up to the full dose. (For more details on light therapy, see "Lights On.")

In my clinical practice, I have helped many people overcome SAD by suggesting they enjoy a "green-light bath," ideally nude. I particularly recommend green light for therapy taken in the evening, when broad-spectrum white light may be too stimulating. Green light seems to lower levels of the stress hormone cortisol, which is beneficial because people with depression and SAD usually have higher cortisol levels as well. You can bathe under a green light to calm your central nervous system. Screw a 150-watt green light bulb into any standard fixture that accepts the high wattage. I like to read to my daughter at night under a green light rather than a bright-white light, because it helps both of us sleep more soundly.

The Tryptophan Connection

Hormones that tie in with SAD include not just melatonin and serotonin, but also the amino acid tryptophan. Serotonin is derived from tryptophan, and both play an important role in how light therapy works. According to one study from the National Institute of Mental Health, patients with SAD who had improved with daily 10,000-lux light therapy were given a tryptophan-free amino acid beverage, which in turn reversed the benefit of the light therapy (Archives of General Psychiatry, 1998, vol. 55, no. 6). Therefore, it's a good idea to add tryptophan-rich foods to your diet while undergoing light-therapy treatments.

Increase your own natural tryptophan levels by eating a meal featuring complex carbohydrates—breads, cereals, legumes, rice, or pasta—at least once a day. Most of us, with or without SAD, have noticed increased carbohydrate cravings in the winter, likely because our melatonin levels are higher and serotonin levels lower. Snacks containing refined sugar don't do the trick; in fact, sugar makes depression worse. But the vegetable starches in foods such as carrots, potatoes, bananas, dates, and figs all raise the body's tryptophan levels, and therefore serotonin levels, for several hours after eating. If you prefer to use supplemental tryptophan, choose the concentrated form—5-hydroxytryptophan (5-HTP), a serotonin-boosting amino acid available at most natural products stores. Take 50 to 200 mg at bedtime to ward off SAD-type depression.

Other Natural Treatments

Many other natural remedies can help decrease the effects of SAD or the winter blues. The first step is to seek out more natural light. This means spending as much time as possible outside this winter, even in muted sunlight, especially if you can get well away from buildings and receive light in a 360-degree radius. Twenty minutes outside daily is a minimum requirement for well-being, and it's best if you move vigorously because exercise itself is a natural antidepressant. Be sure to use sunscreen if you are out between 10 a.m. and 4 p.m. and live in an area with strong sunlight all year round. If you can't get outdoors, sitting indoors near a window with a strong source of natural sunlight can also boost your mood.

If you just can't get enough sunshine in the winter months to prevent SAD, try to increase your vitamin D intake. Formed naturally by the action of sunlight on the skin, vitamin D is a prohormone—that is, a chemical that can be converted into a hormone. Vitamin D deficiency is linked to various health problems, including bone disorders, several hormonal cancers, impaired immune response, hypertension, multiple sclerosis, and mood disorders, including SAD. Good food sources of vitamin D include eggs, liver, fish, and lots of fortified milk. My favorite vitamin D supplement (besides sunshine) is cod-liver oil. One teaspoon taken daily provides about 400 to 600 IU. Do not take cod-liver oil in the first trimester of pregnancy because of its high levels of vitamin A, which can accumulate in the fetal liver and cause damage to the cells.

A high-potency B-complex multivitamin is also critical because vitamin B deficiency is often a physical cause of depression. Stress depletes vitamin B and, for many, the low levels of light in the winter are profoundly stressful.

Lavender, lemon verbena, and scutellaria may all help ward off SAD. Plants also offer many defenses against SAD, not only as vessels of distilled sunlight, but as central nervous system nutrients. Plant nervines—substances that calm the nervous system—are widely available in natural products stores and can be matched to your particular needs by a skilled herbalist or naturopathic doctor. You can start by learning more about lavender (Lavandula angustifolia), which, when inhaled, triggers an olfactory nerve impulse that leads directly to the brain and helps ward off SAD and depression; lemon verbena (Lippia citriodora), which is good for depression accompanied by stomach upset; and scutellaria (Scutellaria baicalensis), which is helpful for depression associated with constipation or headaches. By combining these plant nervines with the right foods and supplements—and, of course, getting plenty of light in your life—SAD symptoms should soon be a thing of the past.